WASHINGTON (CNN) -- The Department of Homeland Security will investigate a Halloween costume party hosted by a top immigration official and attended by a man dressed in a striped prison outfit, dreadlocks and darkened skin make-up, a costume some say is offensive, the department's secretary said.

Julie Myers, head of Immigration and Customs Enforcement, called the man's costume "offensive."

Julie Myers, head of Immigration and Customs Enforcement and host of the fundraising party, was on a three-judge panel that originally praised the prisoner costume for "originality."

Myers later apologized for "a few of the costumes," calling them "inappropriate and offensive." She said she and other senior managers "deeply regret that this happened."

A department photographer photographed Myers with the man, but the images were deleted after the costume were deemed offensive, ICE spokeswoman Kelly Nantel said.

Between 50 and 75 people attended the party, which was a fundraiser for the Combined Federal Campaign, a federal government collection of charities.

Nantel said one employee, whom she declined to identify, was wearing a black-and-white striped prison outfit, dreadlocks and a skin "bronzer" intended "to make him look African-American." But, she said, it was not immediately apparent that he was wearing the make-up.

"Most people in the room didn't realize he was wearing make-up at all," she said.

"It was unintentioned. The employee did not mean to offend although there were some employees that were rightfully offended by it," Nantel said.

Myers and the other judges "noted his costume for originality."

"There were a couple of people who were offended," Nantel said. "When it was confirmed through a conversation with the employee that he was wearing make-up," Nantel said, the employee was counseled and Myers sent out a note to employees apologizing.

In a November 2 email to ICE employees, Myers wrote, "It is now clear that, however unintended, a few of the costumes were inappropriate and offensive. While we were all thrilled to be a part of the CFC fundraising effort, I and the senior management at ICE deeply regret that this happened."

She reminded all employees to be compliant with the department's diversity training requirement.

Myers has served as head of ICE since January of 2006 but is still awaiting Senate confirmation.

An ICE congressional liaison said ICE officials briefed congressional staffers about the costume party this week as a courtesy. But at least one congressional staffer said they approached ICE after receiving an anonymous fax about the incident.

Myers called House Homeland Security Chairman Bennie Thompson, D-Mississippi, about the incident and is expected to meet with him before the end of the week, a Thompson spokeswoman told CNN.

Myers also contacted the National Association of African-Americans in the Department of Homeland Security. In a letter to NAADHS members, the group's vice president, Sjon Shavers, said the group "appreciates (Myers) reaching out to us so quickly in order to keep us apprised of the matter and we commend her on moving so swiftly toward appropriate corrective action."

As head of ICE, Myers heads the law enforcement agency charged with enforcing immigration law inside the United States. It is the second largest investigative agency in the federal government, with more than 15,000 employees, including 6,000 investigators.

"The Secretary has asked for an inquiry into the facts surrounding the incident. Once the facts have been determined, we will take all necessary and appropriate actions," Keehner said.E-mail to a friend